vram?

[DickNixonArisen]

someone told me that my extra CV (which will not display anything correctly, games look like chessboards) has a bad VRAM chip. What does this mean exactly?

 

It's not a dirt issue, I cleaned it and the carts well without affecting the issue.

[Pixelboy]

someone told me that my extra CV (which will not display anything correctly, games look like chessboards) has a bad VRAM chip. What does this mean exactly?

"VRAM" is short for "Video RAM". In the ColecoVision, VRAM is composed of a small group of RAM chips associated to the CV's main graphic display processor. If one of these chips go bad, you get corrupted graphics on the screen. It's as simple as that.

[DickNixonArisen]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

[Pixelboy]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

Yurkie fixed a bad RAM chip for me, so he could certainly help you out.

[channelmaniac]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

 

There are 8 video RAM chips in the CV. You can always remove all 8 and modify the system to use +5v only DRAM. This will make it run cooler and more reliably.

 

The current DRAM in the system is 4116. These require +5, +12, and -5v. The +12 and +5v is switched by the CV's power switch and the -5v is always on. The modification removes the +12v and -5v connections from the chips and replaces the chips with sockets and either 4516 or 4164 DRAM chips.

 

These 5v only DRAMs don't suffer from the dirty power switch issues that the 4116s have.

 

I have complete kits on my site. They come with the chips, sockets, and a short piece of kynar wire to install a required jumper. Instructions are on the downloads section if you have the chips and want to do it yourself.

 

http://www.arcadecomponents.com/modkits.html

 

RJ

[Ikrananka]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

 

There are 8 video RAM chips in the CV. You can always remove all 8 and modify the system to use +5v only DRAM. This will make it run cooler and more reliably.

 

The current DRAM in the system is 4116. These require +5, +12, and -5v. The +12 and +5v is switched by the CV's power switch and the -5v is always on. The modification removes the +12v and -5v connections from the chips and replaces the chips with sockets and either 4516 or 4164 DRAM chips.

 

These 5v only DRAMs don't suffer from the dirty power switch issues that the 4116s have.

 

I have complete kits on my site. They come with the chips, sockets, and a short piece of kynar wire to install a required jumper. Instructions are on the downloads section if you have the chips and want to do it yourself.

 

http://www.arcadecomponents.com/modkits.html

 

RJ

Will you be getting the kits back in stock - they're showing as out of stock at the moment?

 

If just buying the chips is there a preference for the 4516 or 4164, e.g. lower power drain, more efficient (less heat generated)? I noticed that you have various speeds available for the 4164 chips. Does it matter which speed of chip is used?

 

Thanks

Edited February 1, 2011 by Ikrananka

[+Yurkie]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

 

It's more likely a dirty power switch is your problem.

[tz101]

If its a dirty power switch, then most likely a can of electronic contact cleaner from Radio Shack should do the trick. I had an Intellivision console that only displayed a black screen on start up. I sprayed the power switch with this cleaner and switched it back and forth a few times, and it fixed the problem.

[+Yurkie]

If its a dirty power switch, then most likely a can of electronic contact cleaner from Radio Shack should do the trick. I had an Intellivision console that only displayed a black screen on start up. I sprayed the power switch with this cleaner and switched it back and forth a few times, and it fixed the problem.

 

The switch needs to be removed from the board dissembled and cleaned/re-greased. The way the switch is made there really is no way to get cleaner on the contacts without disassembly.

 

If you try a DIY on the switch be careful not to damage the traces on the PCB when you remove it.

[Ikrananka]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

 

It's more likely a dirty power switch is your problem.

I suppose this is what happens when I hijack an old thread - the original poster's problem was back in May 2010. I just had a vram question so if anyone can help with that I'd be most grateful. I don't have a graphics problem at the moment but am working on an internal power mod and considering changing the vram to improve options on the power mod when the number of different volatages is reduced.

[Ikrananka]

So what are my chances of finding a chip and soldering a new one on? Probably need a second scrap CV with a different issue, I bet..

 

my main deck still works well at least

 

It's more likely a dirty power switch is your problem.

I suppose this is what happens when I hijack an old thread - the original poster's problem was back in May 2010. I just had a vram question so if anyone can help with that I'd be most grateful. I don't have a graphics problem at the moment but am working on an internal power mod and considering changing the vram to improve options on the power mod when the number of different volatages is reduced.

This thread has answered my questions - I should learn to search better!!!

 

http://www.atariage.com/forums/topic/130195-colecovision-components-question/

[Madaracs]

If its a dirty power switch, then most likely a can of electronic contact cleaner from Radio Shack should do the trick. I had an Intellivision console that only displayed a black screen on start up. I sprayed the power switch with this cleaner and switched it back and forth a few times, and it fixed the problem.

 

Not to contradict, but you mayn't want to use electronic contact cleaner on the CV switch. Because as Egon would say, "It would be bad." And although life as you know it would continue on and every molecule in your body might remain stable, the switch in the CV has conductive grease in it that it is necessary for normal operation.

 

If you use contact cleaner on it, the grease will likely be eaten away and the switch might operate OK for awhile (or not at all if you tighten your CV screws too much upon reassembly.) The switch really should be reconditioned as Yurkie mentions.

 

Also, you should never use contact cleaner to clean cassette decks. I'm not sayin'... but I'm just sayin'.

[+Yurkie]

 

Not to contradict, but you mayn't want to use electronic contact cleaner on the CV switch. Because as Egon would say, "It would be bad." And although life as you know it would continue on and every molecule in your body might remain stable, the switch in the CV has conductive grease in it that it is necessary for normal operation.

 

If you use contact cleaner on it, the grease will likely be eaten away and the switch might operate OK for awhile (or not at all if you tighten your CV screws too much upon reassembly.) The switch really should be reconditioned as Yurkie mentions.

 

Also, you should never use contact cleaner to clean cassette decks. I'm not sayin'... but I'm just sayin'.

 

Sorry to have to correct you but the grease is NOT conductive. Dielectric grease simply provides lubricity and protects against corrosion.

[Madaracs]

 

Not to contradict, but you mayn't want to use electronic contact cleaner on the CV switch. Because as Egon would say, "It would be bad." And although life as you know it would continue on and every molecule in your body might remain stable, the switch in the CV has conductive grease in it that it is necessary for normal operation.

 

If you use contact cleaner on it, the grease will likely be eaten away and the switch might operate OK for awhile (or not at all if you tighten your CV screws too much upon reassembly.) The switch really should be reconditioned as Yurkie mentions.

 

Also, you should never use contact cleaner to clean cassette decks. I'm not sayin'... but I'm just sayin'.

 

Sorry to have to correct you but the grease is NOT conductive. Dielectric grease simply provides lubricity and protects against corrosion.

 

I don't mind. I read somewhere a long time ago that it was conductive. (on the reliable internets) Better to be corrected then go on believing something that isn't true.

[+5-11under]

The contact cleaner might be a good first start, if you're not sure what the problem is.

[Pixelboy]

I was thinking of attempting to grease up the ON/OFF switch on one of my CV consoles with strawberry jam. That should work, right?

 

If not, I can always try peanut butter...

 

 

 

 

[Ikrananka]

I was thinking of attempting to grease up the ON/OFF switch on one of my CV consoles with strawberry jam. That should work, right?

 

If not, I can always try peanut butter...

 

 

 

 

Just don't be tempted to lick it off - otherwise the benefits of the jam and/or peanut butter will be lost. Plus you run the risk of a tingling tongue of you were to lick it while powered up.

[channelmaniac]

At the speed the CV runs at you can use 200ns, 150ns, 120ns, or 100ns DRAM just fine without any issues.

 

Of course, it's best to have matching speed DRAMs but at that slow speed you can mix/match DRAM speeds and manufacturers with little issue.

 

For the switch, you can pick up dielectric grease at any automotive store. It's used for installing spark plugs as a little bit in the boot keeps the boot from sticking to the plug so you can remove them without the wire pulling out of the boot. Little bits of boot sticking on the plug makes it difficult to get a socket it so you can remove it during troubleshooting or tune-ups.

[boardjunkie]

At the speed the CV runs at you can use 200ns, 150ns, 120ns, or 100ns DRAM just fine without any issues.

 

Of course, it's best to have matching speed DRAMs but at that slow speed you can mix/match DRAM speeds and manufacturers with little issue.

 

For the switch, you can pick up dielectric grease at any automotive store. It's used for installing spark plugs as a little bit in the boot keeps the boot from sticking to the plug so you can remove them without the wire pulling out of the boot. Little bits of boot sticking on the plug makes it difficult to get a socket it so you can remove it during troubleshooting or tune-ups.

 

Actually, the silicone grease is for sealing out moisture. The combination of dirt/contaminants and moisture can form a conductive arc path from the connector in the wire right down the plug where it arcs to gnd. I've seen this happen too many times to count. Ever have a car that is hard to start or misses badly on rainy days? This is why.